Efforts began Thursday to empty the fuel tanks of a Slovakian freighter that capsized over the weekend off Denmark, reported dpa. Once the fuel tanks have been emptied, rescue workers aimed to turn the almost 80-metre-long vessel onto an even keel. Three of the 11-strong crew, all Turkish nationals, survived the accident Sunday while the bodies of four other crew members have been retrieved. Four crew members of the Omer N were still missing. Their bodies were believed to be trapped in the hull, Danish marine rescue services said. The freighter was heading to France with a cargo of fertilizer from Gdynia, Poland, when it capsized in the Fehmarn Belt strait located between the German and Danish coasts. The reason for the accident remains unclear.